The richest 1% of New York City residents are living in multimillion-dollar Frankenmansions

One mega-mansion in New York City, outlined in red.Google Street View/Screenshot

When an apartment or penthouse isn't big enough for wealthy New Yorkers, they get creative.

In recent years, several have combined multiple townhouses or building floors to create supersized homes — or Frankenmansions, as New York magazine's S. Jhoanna Robledo calls them.

To construct these Frankenmansions, some prospective buyers purchase multiple buildings at once, while others approach their neighbors to offer multimillion-dollar buyouts. (In either scenario, they need the city's approval before combining properties.)

A $19.8 million pair of townhouses is currently on the market.

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The Missionary Sisters of the Immaculate Heart of Mary, an NYC-based convent of nuns, acquired the townhome on the right in 1948. Four years later, the group bought the one next door and connected them via a doorway on each floor.

Throughout the years, the order has rented some of the complex's 25 bedrooms to other congregations or young women in need. But the Frankenmansion may soon find a new owner — the 15,600-square-foot space went on the market in 2016 for $19.8 million, according to The New York Times.

The 13,900-square-foot mansion includes nine bedrooms, eight bathrooms, a 2,100-square-foot private garden, and five floors.

Napster cofounder Sean Parker paid $58.5 million for his mega-mansion.

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Sean Parker, the former president of Facebook, owns the three brownstones pictured above. Each building originally contained four apartment units, a grand stairwell, and a rear garden. The interior spaces feature arched doorways and original 19th-century fireplaces with marble mantles.

Parker purchased the first building for $20 million in 2010, the second for $16.5 million in May 2016, and the third for a reported $22 million in August 2016. He completed the renovation to connect all three in late 2016.

Once a factory and showroom, these buildings will soon be one Frankenmansion.

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The billionaire Jon Stryker is the rumored owner of the two brick buildings above, which the NYC-based firm Steven Harris Architects is working to turn into one residence. Curbed reported that Stryker was likely the buyer of the $32 million set in 2012. The renovation project was approved by the city in October.

In their former lives, the buildings were an ice cream factory, a Steinway piano showroom, and a garage. The property's facade will stretch 41 feet.

Madonna's $32 million Frankenmansion has 13 bedrooms.

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In 2009, Madonna bought three connected townhouses on Manhattan's Upper East Side. The $32 million mansion features 13 bedrooms, a dance studio, multiple dining rooms, a 3,000-square-foot garden, two garages, an elevator, and a private gym, according to Curbed.

Roman Abramovich is working to connect a trio of townhouses worth $78 million.

The facades will be preserved, and the center house will become the mansion's main entrance after construction is complete. The interiors will be completely renovated, and the backyard will feature a private garden.

A pair of limestone townhouses is listed for $75 million.

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Owned by the billionaire Safra family, the two limestone townhouses above were listed for sale in 2015 as a trio with the building on the right. The asking price was $120 million, but in 2016, the owners asked for $75 million for just the pair, which sold in early 2017 and will likely be combined, according to Curbed.

The musician Michael Feinstein has a $17.9 million brownstone duo.

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Feinstein bought the townhome on the left for $3 million in 2004, according to The New York Times. A year later, the one next door went up for sale for $3.8 million, and Feinstein purchased, gutted, and renovated it to connect the two.

The finished product features 18 rooms, twin staircases, seven bathrooms, two powder rooms, eight fireplaces, a 25-foot-wide backyard, and two pagodas, which serve as outdoor living and dining areas. He put the mansion on the market for $17.9 million in 2013 but later decided to keep it.

Dexter Goei, the CEO of the telecoms company Altice, plans to combine these two townhouses in Manhattan's Greenwich Village neighborhood.

The Real Deal reported in October that converting them into a mega-mansion was expected to cost $1.3 million. The renovation will be led by the architecture firm Arcologia.

The artist Jeff Koons melded these two townhomes east of Central Park.

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Jeff Koons, the artist known for his giant sculptures of balloon animals, purchased the townhomes pictured above for $32 million in 2009, according to Curbed.

A year later, he applied to NYC's Department of Buildings to combine them into a 21,500-square-foot mega-mansion, but the request was denied. In 2013, he submitted a revised proposal, and the renovation started soon after.

Lauren Bush Lauren purchased a trio of West Village townhomes, combined by the previous owner, renowned photographer Annie Leibovitz.

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Lauren Bush Lauren, the granddaughter of former President George H.W. Bush, bought a trio of townhouses for $28.5 million in 2014, along with her husband, David Lauren, the New York Post reported.

The renowned photographer Annie Leibovitz was the previous owner. She bought the first two townhouses in 2002 for $4.2 million. A year later, she purchased the neighboring one on the corner for $1.9 million, then combined the three.